The present invention relates to an improved coil spring counterbalance assembly for use on vertically sliding window sashes wherein the improved assembly hereof incorporates structural embodiments which substantially enhance the smoothness of counterbalance sash operation as well as the ease and facility with which one may install and connect multiple spring components one to the other and to the sash attached balance shoe connector when more than one spring component is required in order to adequately counterbalance a particular sash.
As shown in Applicant's previous teaching, in U.S. Pat. No. 4,935,987 dated Jun. 26, 1990, to Sterner, and in particular as illustrated in FIGS. 2, 3 and 4 thereof, the respective counterbalance springs are each supported by a hub insertably installed through the core openings thereof, upon which hub a coil spring rotates in feeding out and retracting the coil ribbon thereof during vertical movement of a sash in opening and closing operations. Each of the coil spring ribbons has a ribbon core tail ending that in consequence cyclically snaps over the support hub in radius adjustment as the coil spring radius decreases or increases upon sash movement whereby the coil spring radius snapping adjustment effect in turn causes both a distinct and audibly distracting sound in addition to any annoying sash vibration, which sound and vibration effects become more pronounced with the use of multiple coil springs to balance a sash. The counterbalance coil spring sub-assembly as taught in U.S. Pat. No. 4,227,345 to Durham, Jr., dated Oct. 14, 1980, and best illustrated in FIG. 5 thereof, shows a structure in some respects similar to that herein taught but is distinguished in that the coil spring of Durham, Jr., is attached to and supported by the mounting bracket hub thereof.
Other coil spring sash balance hardware apparatus provide for coil support about the external circumferential surface of the spring, such as those respectively taught in U.S. Pat. No. 3,150,420 to Brenner, dated Sept. 29, 1964, and U.S. Pat. No. 3,452,480 to Foster, dated Jul. 1, 1969.
Prior art coil spring counterbalance devices of the external circumferential support category do avoid the snapping sound and sash vibration effects, but do not adapt well to use in applications requiring multiple springs for the counterbalancing of heavier sashes.
The applicant's improved coil spring counterbalance assembly, however, mechanically provides a structural capability to both enhance the ease and smoothness of sash operation as well as at the same time providing a connection method for joining successive coil spring ribbons in sash counterbalancing applications requiring a use of multiple coil springs, all in a manner as hereinafter more fully detailed and described.